Electrochemical capacitors, also referred to as supercapacitors, function as “fast batteries” by supplying high amounts electrical energy on short time scales, with rapid switching speeds, and long-term cycle stability. Supercapacitors have been proposed to bridge the gap between batteries and capacitors by incorporating elements of both technologies. Carbon is attractive due to its chemical and thermal stability; however, the maximum attainable gravimetric capacitance is around 150-200 F/g in aqueous electrolytes and 120-150 F/g in non-aqueous electrolytes. In these systems, charge is stored by a purely physical mechanism at the interface of inert carbon electrodes within the so-called “electrical double-layer” and is fundamentally limited by surface area. Compared to batteries, which store charge through chemical reactions within the electrode, supercapacitors suffer from low energy density or charge capacity. In light of the current need for higher energy and power densities, there is a need for technologies and materials that can overcome the existing limitations of pure carbon capacitors.